Possible Duplicate:
Copying an Object in Javascript
How can I create a new object from other object? Something like copy constructor in other languages like C#.
views:
141answers:
5
A:
Alsciende
2010-03-04 18:55:18
The `prototype` property should be used on Constructor Functions, on object instances *has no special meaning*, there is a lot of confusion between that property with the internal `[[Prototype]]` property...
CMS
2010-03-04 18:57:08
This looks like an interesting solution, but in testing it doesn't work.
Renesis
2010-03-04 18:59:44
right, my mistake. i'll correct it
Alsciende
2010-03-04 19:11:41
+2
A:
There is no built-in framework for copying in JS. Many of the simple types are immutable value types which you can just copy the references of. Array and Object you can write a function to copy for you, eg.:
function copy(o, isdeep) {
if (o===undefined || o===null || ['string', 'number', 'boolean'].indexOf(typeof o)!==-1)
return o;
var n= o instanceof Array? [] : {};
for (var k in o)
if (o.hasOwnProperty(k))
n[k]= isdeep? copy(o[k], isdeep) : o[k];
return n;
}
However for every other type of object you will have to write your own copy code. Many built-in objects are inherently uncopiable.
bobince
2010-03-04 19:02:46
I think that OP meant 'clone' object and not 'copy' (event if he didn't say so). You show how to create a new instance of an object with copy of all its properties (e.g. same property in the result object will point to the same memory as the property of source). This mean that changing some property in source object will change this property in destination object.
Kamarey
2010-03-04 19:54:55
A:
//
function copycat(obj){
if(!obj.constructor) return obj;
var cop= new obj.constructor;
for(var p in obj){
if(obj.hasOwnProperty(p)){
cop[p]= obj[p];
}
}
return cop;
}
var a= [1, 2, 3, 4, 5];
var o={x:100,y:100,z:100};
var b=copycat(a);
var o2=copycat(o);
kennebec
2010-03-04 19:26:52
A:
Kamarey
2010-03-04 19:42:29